Embodiments of the present invention relate to contactless transactions conducted using a Near Field Communication (NFC) controller coupled to at least one host processor.
NFC technology is currently being developed by an industrial consortium grouped under the name “NFC Forum” (http://www.nfc-forum.org). NFC technology is derived from Radio Frequency Identification (RFID) technology and uses NFC controllers having several operating modes, in particular a Reader mode and a Card Emulation mode.
FIG. 1 shows an NFC device generally termed “NFC chipset” including an NFC controller NFCC and at least one host processor HP1 linked to the controller NFCC by a bus BS1, for example of the Single Wire Protocol (SWP) type. The host processor may take the form of an integrated circuit designated Universal Integrated Circuit Card (UICC), such as a Subscriber Identity Module (SIM) card. The host processor may also be the baseband processor of a mobile telephone (that is, the processor in charge of telephonic communications). The resources of the controller NFCC are available to the host processor HP1 to allow it to manage contactless applications. The controller NFCC includes a host controller HC and a contactless interface CLF (“Contactless Front End Interface”) equipped with an antenna coil AC1. In practice, the host controller HC and the interface CLF may be made on the same semiconductor chip, such as the MicroRead® chip commercialized by the applicant, or may be two distinct chips, such as the chips “PicoRead® Microcontroller” and “PicoRead® RF Interface” commercialized by the applicant.
The interface CLF of the controller NFCC can generally operate according to several RF technologies designated RFTi in FIG. 1, for example “Type A” or “Type B”, such as defined by ISO/IEC 14443 parts 2, 3, and 4; “Type B”, such as defined by ISO/IEC 14443-2 with a standard framing such as defined by ISO/IEC 14443-3; and “Type F”, such as defined by ISO 18092 in passive mode at 212 and 424 kilo octets per second (kops), or by the Japanese Industrial Standard JIS X 6319-4. Each RF technology, or contactless communication protocol, defines an emission frequency of the magnetic field, a method of modulating the magnetic field to transmit data in active mode, a method of charge modulation to transmit data in passive mode, a method of data coding, a data frame format, and the like.
Due to its wide communication capabilities, such an NFC device is generally integrated in a portable device HD (“Handheld Device”) such as a mobile telephone, a Personal Digital Assistant (PDA), or the like. Application examples of the NFC device are shown in FIG. 2, which shows a portable device HD equipped with the NFC device of FIG. 1, the device HD of FIG. 2 is in the form of a mobile telephone. Reader Applications RAP and Card Applications CAP may be distinguished.
Reader Applications (RAP)
The controller NFCC operates as an NFC reader to conduct a transaction with a Contactless Integrated Circuit CIC. A reader application RAPi is executed by the host processor HP1 (FIG. 1). The host processor HP1 sets the interface CLF in an active operating mode where it emits a magnetic field FLD, sends data by modulation of the magnetic field, and receives data by charge modulation and inductive coupling. This type of application may be free (for example, reading a tag containing the bus schedules at a bus stop) and may be executed by an unsecure processor. The host processor HP1 may, in this case, be the baseband processor of the mobile telephone. If it is a paid application, the host processor HP1 is preferably a secure processor (for example, a processor of a SIM card), because the access to the service requires an identification of the subscriber.
Card Applications (CAP)
The operating principle of the card emulation mode is described by the patent EP 1 327 222 (U.S. Pat. No. 7,098,770) in the name of the applicant. A card application (CAPi) is executed by the host processor HP1 (FIG. 1). The host processor HP1 sets the controller NFCC in a passive operating mode and forms, with the controller NFCC, the equivalent of a contactless integrated circuit, which is seen by a reader RD as a contactless card. Thus, the controller NFCC does not emit a magnetic field, receives data by demodulating a magnetic field FLD emitted by the reader RD, and emits data by modulating the impedance of its antenna circuit (charge modulation). The related applications are generally applications for payment or payment access control (payment machine, subway entrance, or the like.). The portable device HD is therefore used in this case as a chip card. This type of application is most often secure, and the host processor HP1 that executes the application program is in this case a secure processor, for example a SIM card processor.
Standardized Architecture of an NFC Device
Inside the NFC device, the bus BS1 generally supports communication interfaces called HCI (“Host Controller Interface”) by the intermediary of the controller NFCC and the host processor HP1 exchanging data in conformance with the Host Controller Protocol HCP. This protocol provides a routing of data according to routing channels called “pipes” described in the applications EP 1 855 229 (US 2007/0263595) or EP 1 855 389 (US 2007/0263596) in the name of the applicant.
The HCI interface and the HCP protocol are also described in the European Telecommunications Standards Institute's ETSI TS 102 622 specification entitled “Smart Cards; Universal Integrated Circuit Card (UICC); Contactless Front-end (CLF) interface; Host Controller Interface (HCI)”. In addition, the commands and the responses to commands exchanged during a transaction between the host processor HP1 and an external device, such as the passive contactless integrated circuit CIC or the reader RD, are defined by the NFCForum-TS-Type-4-Tag specifications entitled “Type 4 Tag Operation”. Equally, the format of data exchanged during an NFC transaction is defined by the NFCForum-TS-NDEF specifications entitled “NFC Data Exchange Format (NDEF)”.
As shown in FIG. 1, these diverse specifications define an NFC device architecture wherein the controller NFCC executes one or more RFTi technologies (operating modes of the interface CLF, for example Type A, Type B, Type B′, and Type F), whereas the host processor HP1 executes reader applications RAPi and card applications CAPi. Each technology RFTi is accessible by the intermediary of a Reader RF Gate RRFG or by a Card RF Gate CRFG. Each reader application RAPi includes a Reader Application Gate RAG that is connected by the intermediary of a pipe to a reader RF gate RRFG associated with a technology RFTi. Similarly, each card application CAPi comprises a Card Application Gate CAG that is connected by the intermediary of a pipe to a card RF gate CRFG associated with a technology RFTi. With each reader gate RRFG or card gate CRFG is associated a registry that contains parameters necessary for the management of the RF channel according to the technology RFTi that the reader application or the card application uses.
Commands Exchanged During the Execution of a Reader Application
During the execution of a reader application RAPi, the host processor HP1 configures the interface CLF in active mode by the intermediary of a reader application gate RAG. The reader application RAPi activates a gate RAG and requests the HCI administrator (software unit executed by the controller NFCC) to open a pipe P1 between the gate RAG and a gate RRFG associated with a desired technology RFTi. The application RAPi then emits commands CAPDU that are transmitted to the controller NFCC by the intermediary of the pipe P1, then are transmitted to the integrated circuit CIC by the intermediary of an RF channel. The contactless integrated circuit CIC sends back responses RAPDU to the controller NFCC, which the controller NFCC then transmits to the host processor HP1 via the intermediary of the pipe P1.
Commands Exchanged During the Execution of a Card Application
During the execution of a card application CAPi, the host processor HP1 emulates a passive contactless card and uses the interface CLF in passive mode. The card application CAPi activates a gate CAG and requests the HCI administrator to open a pipe P2 between the gate CAG and a gate CRFG associated with a desired technology RFTi. The reader RD sends to the controller NFCC commands CAPDU that the controller NFCC transmits to the host processor HP1 by the intermediary of the pipe P2. The host processor HP1 emits responses RAPDU that are transmitted to the controller NFCC via the intermediary of the pipe P2. The responses are then transmitted by the controller NFCC to the reader RD, by the intermediary of an RF channel.
The commands CAPDU and the responses RAPDU (generally designated “C-APDU” and “R-APDU”) are defined by the standard ISO 7816-4 and are detailed at point 5 of the “Type 4 Tag Operation” specification.
In summary, the host processor HP1 emits commands CAPDU when operating in reader mode and conducts a transaction with a contactless integrated circuit CIC, and the contactless integrated circuit CIC sends back responses RAPDU to the host processor HP1. Inversely, when operating in card emulation mode, the host processor HP1 receives commands CAPDU emitted by a reader RD and sends back responses RAPDU to the reader RD.
It is known that the development of NFC technology is closely linked to the development of applications of the card emulation type, which allow for the use of a portable device HD as a contactless chip card. Even though infrastructures equipped with NFC readers already exist, in particular in the domain of access control, these infrastructures are rare and are not developing at a sufficient rate to allow for the desired development of NFC technology. In particular, a constraint that is impeding the development of NFC infrastructures is the cost of NFC readers themselves, as well as the cost of their installation in the application areas. As a reader is an active device that emits a magnetic field, it presents a certain complexity and non-negligible cost, and must be linked to an electrical power supply.
It may therefore be desired to provide a method of conducting an NFC transaction and an NFC system that allows for the implementation of card applications without the constraint of requiring the installation of a group of readers.